When I first set out to contact all the adjuncts at GCC on a regular basis (there are 648 as of this morning), I quickly realized that the only sure way was to send a letter to everyone's home address.  This would cost about $250 dollars for each mailing.  If I were to send postcards to everyone's home instead, the cost would "only" be about $160.  As my communication model evolved into a campus newsletter sent to everyone's folder/mailbox, the term "postcards" stuck in my mind for a number of reasons.  The obvious one is that each item in the newsletter is effectively a "postcard" and the newsletter is a collection of them.  There is also some reference to the book/movie Postcards from the Edge, but the allegory is thin at best.  The main reason, of course, I just happened to like the sound of it ;)